Methods and materials for monitoring myeloma using quantitative mass spectrometry

ABSTRACT

The subject invention concerns methods and materials for diagnosing, monitoring the progress, and/or providing a prognosis for multiple myeloma and other conditions associated with antibody production in a person or animal. The methods of the invention utilize mass spectrometry for quantitative monitoring and detection of antibody produced by the plasma cells. The methods of the invention can be utilized for diagnosis, monitoring, and/or prognosis of multiple myeloma, monoclonal gammopathy, and other immunological or hematological conditions and disorders. In addition to detecting and quantifying antibody in a sample, other biological markers, such as serum albumin and/or beta-2-microglobulin, can also be detected and quantified using the present invention, and in combination with detection and quantification of antibody. Thus, in one embodiment, both antibody and serum albumin and/or beta-2-microglobulin are detected and quantified using mass spectrometry and a diagnosis or prognosis made based on the results and levels detected.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication Ser. No. 61/076,907, filed Jun. 30, 2008, which is herebyincorporated by reference herein in its entirety, including any figures,tables, nucleic acid sequences, amino acid sequences, and drawings.

BACKGROUND OF THE INVENTION

Multiple myeloma (MM) is a cancer of the plasma cell, which primarilydevelops in the elderly population. The progression of the tumor is wellunderstood, and it can be diagnosed by the presence of multiple myelomacells in the bone marrow and monitored by the amount of antibodysecretion from the clonal population of plasma cells. A premalignantcondition known as monoclonal gammopathy of undetermined significance(MGUS) develops at certain rates in the U.S. population: 3% at age 50,5% at age 70, and 7% by age 85; approximately 1% of MGUS patientsprogress to multiple myeloma on an annual basis (Kyle et al., 2006). Themolecular causes for progression from MGUS to MM are unknown. After theonset of the cancer, multiple myeloma patients suffer from severalsymptoms, including calcium dysregulation, renal failure, anemia, andbone lesions. A diagnosis of multiple myeloma is established using bloodand urine tests. For advanced stage patients, complete skeletal surveysare also used to examine the damage caused by multiple myeloma in thebone marrow. Staging with serum calcium, creatinine, hemoglobin, andmost importantly, the concentration of the “monoclonal serum protein”was established in 1975 by Durie and Salmon (Durie and Salmon, 1975).The International Staging System determined in 2005 uses those markersas well as serum albumin and β-2-microglobulin (Greipp et al., 2005).The survival statistics indicate the importance of early detection andproper staging, and show the devastating impact of multiple myeloma.Stage I patients have median survival times of 62 months, stage II 45months, and stage III patient median survival is reduced to 29 months.

Despite the highly specific and easily detectable biomarkers, manychallenges still exist for MM treatment. Several different treatmentregimens are under investigation; these strategies have been the subjectof numerous recent reviews (Fonseca and Stewart, 2007; Chanan-Khan andLee, 2007; Thomas and Alexanian, 2007; Falco et al., 2007). Noveltherapeutic strategies include proteasome inhibition with agents likebortezomib (Voorhees and Orlowski, 2007; Manochakian et al., 2007) and acombination of cancer cell targeting and immune modulation withthalidomide derivatives like Lenalidomide (Singhal and Mehta, 2007).While each of these agents can have some success against multiplemycloma cells, proteasome inhibitors are the only molecularly guidedtherapy to date: treatment is more effective for patients with myelomasthat secrete high levels of monoclonal antibodies (Meister et al.,2007). The use of the other agents is directed by the expected tolerancefor side effects rather than molecular targeting. Regardless, theseagents improve the patient outcome when compared to the current standardof care (Ma et al., 2003), and drug combination strategies are currentlyin clinical trials (Srikanth et al., 2008; Richardson et al., 2007;Merchionne et al., 2007). Proteomic research may contribute to guidanceof existing and emerging therapies. Identification of novel targetsincluding c-Jun and the Fanconi anemia pathway (Chen et al., 2005) alsooffers opportunities to examine protein expression, binding partners,and post-translational modification. Furthermore, the bone marrowmicroenvironment is critical for progression of multiple myeloma andlikely contributes to drug resistance; (Li and Dalton, 2006; Hazlehurstet al., 2003; Dalton, 2003) this knowledge has led to preclinical modelsexamining multiple myeloma in the context of the bone marrowmicroenvironment. Plausible targets in the bone marrow microenvironmentinclude cytokine signaling, e.g. IL-6, (Chauhan et al., 1997; Urashimaet al., 1997) and integrin mediated drug resistance (Damiano et al.,1999). Proteome analysis may make a significant contribution here aswell.

Patient monitoring strategies present significant challenges,particularly in the detection of MGUS patients most likely to developmultiple mycloma and ongoing assessment of relapse or recurrence inpreviously treated multiple myeloma patients. Many MM patients who haveundergone treatment are repetitively checked at two week or four weekintervals, leading to high numbers of clinic visits and collection oflarge volumes of blood. Methods for patient sampling and detection ofthe monoclonal serum protein are presented from a process chemistrystandpoint. Process chemists use extensive background knowledge ofsynthesis, analysis, and engineering to redesign industrial assemblylines or improve individual steps in manufacturing.

BRIEF SUMMARY OF THE INVENTION

The subject invention concerns methods and materials for diagnosing,monitoring the progress, and/or providing a prognosis for multiplemyeloma and other conditions associated with antibody production in aperson or animal. In one embodiment, quantitative mass spectrometry isused to monitor the amount of multiple myeloma cells in patients usingserum samples. Each MM tumor secretes a specific (monoclonal) antibody;the amount of the tumor in the blood or bone marrow of a patient can bemeasured by the detection of this protein. Current methods use gel orcapillary electrophoresis to monitor the relative amount and identifythe type of the antibody that is secreted by the MM cells. Thequantitative mass spectrometry techniques of the present inventioncombines these two measurements and can provide for absolutequantification for each of the antibody chains (A, D, E. G, and M, aswell as kappa and lambda) in MM patients. Proteolytic peptides are usedas surrogate biomarkers to measure the amount of the monoclonal antibodyexpressed in patients' sera. The methods of the present invention can beapplied to MM patients, patients with the premalignant condition,monoclonal gammopathy of undetermined significance (MGUS), and otherimmune or blood disorders, such as Waldenstrom's macroglobinemia orHIV/AIDS. Additional diagnostic markers, including but not limited toserum albumin and beta-2-microglobulin, can also be quantified using thepresent invention.

In one embodiment of a method of the invention, monoclonal antibodyproteins were excised from serum protein electrophoresis gels anddigested with trypsin. Following trypsin digestion, the resultingisolated proteolytic peptides were sequenced with liquid chromatographycoupled to tandem mass spectrometry. Using the results from severalpatient samples, specific peptides were selected to monitor each type ofantibody (A, D, E, G, and M), as well as kappa and lambda light chainand other diagnostic molecules like serum albumin andbeta-2-microglobulin (see Table 1). After selecting peptides that wereconsistently detected in all patient samples, a quantitative assay wasdeveloped using liquid chromatography coupled to multiple reactionmonitoring (LC-MRM) on a triple quadrupole mass spectrometer. Afterovernight digestion of patient serum, the peptides are analyzed in a45-minute experiment separating them by reverse phase and filtering themby molecular weight and sequence specific fragment ions. Using thesetransitions (pairs of intact molecules and fragments), individualpeptide molecules can be selectively quantified, even from a complexmatrix like human blood serum. The methods of the present invention havebeen proven effective with control serum and patient samples. Absolutequantification is obtained by spiking in known amounts of syntheticpeptide containing heavy isotope labels, e.g. ¹³C and ¹⁵N or by creatinga mass shift by substituting an amino acid with one of a similarcomposition (such as Alanine for Glycine).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B depict the antibody production for detected withconventional serum protein electrophoresis for use in multiple myelomadiagnosis and prognosis.

FIG. 2 depicts the antibodies identified using immunofixationelectrophoresis for use in multiple myeloma diagnosis and prognosis.

FIG. 3 depicts the multiple myeloma diagnosis and prognosis method wheremonoclonal spike is an IgG with λ light chain. After LC-MS/MS, peptides,such as ALPAPIEK (SEQ ID NO:4) from IgG, can be selected forquantitative mass spectrometry assays.

FIG. 4 depicts a schematic diagram of selected reaction monitoring usedin multiple myeloma diagnosis and prognosis.

FIG. 5 depicts the abilities of multiple mycloma diagnosis andprognosis, where single molecule can be detected by filtering the m/zvalues for peptide and specific fragments. Using the same serum sampleshown in FIG. 1B, the quantity and type of antibody are determined in amass spectrometry assay; high levels of ALPAPIEK (SEQ ID NO:4) from IgG.

FIG. 6 depicts an assay to confirm the multiple myeloma diagnosis andprognosis method DSTYSLSSTLTLSK (SEQ ID NO:28) from κ light chain wereconfirmed using Multiple Reaction Monitoring.

BRIEF DESCRIPTION OF THE SEQUENCES

SEQ ID NO:1 is a peptide sequence of the invention (IGHA1, 2).

SEQ ID NO:2 is a peptide sequence of the invention (IGHA1, 2).

SEQ ID NO:3 is a peptide sequence of the invention (IGHA1).

SEQ ID NO:4 is a peptide sequence of the invention (IGHG1, 3).

SEQ ID NO:5 is a peptide sequence of the invention (IGHG1, 2).

SEQ ID NO:6 is a peptide sequence of the invention (IGHG1, 2).

SEQ ID NO:7 is a peptide sequence of the invention (IGHG1).

SEQ ID NO:8 is a peptide sequence of the invention (IGHG2).

SEQ ID NO:9 is a peptide sequence of the invention (IGHG3).

SEQ ID NO:10 is a peptide sequence of the invention (IGHG3, 4).

SEQ ID NO:11 is a peptide sequence of the invention (IGHG4).

SEQ ID NO:12 is a peptide sequence of the invention (IGHM).

SEQ ID NO: 13 is a peptide sequence of the invention (IGHM).

SEQ ID NO: 14 is a peptide sequence of the invention (IGHM).

SEQ ID NO:15 is a peptide sequence of the invention (IGKC).

SEQ ID NO:16 is a peptide sequence of the invention (IGKC).

SEQ ID NO:17 is a peptide sequence of the invention (IGKC).

SEQ ID NO: 18 is a peptide sequence of the invention (LAC).

SEQ ID NO: 19 is a peptide sequence of the invention (LAC).

SEQ ID NO:20 is a peptide sequence of the invention (IGHE).

SEQ ID NO:21 is a peptide sequence of the invention (IGHE).

SEQ ID NO:22 is a peptide sequence of the invention (IGHD).

SEQ ID NO:23 is a peptide sequence of the invention (IGHD).

SEQ ID NO:24 is a peptide sequence of the invention (IGHD).

SEQ ID NO:25 is a peptide sequence of the invention (ALBU).

SEQ ID NO:26 is a peptide sequence of the invention (ALBU).

SEQ ID NO:27 is a peptide sequence of the invention (ALBU).

SEQ ID NO:28 is a peptide sequence of the invention.

SEQ ID NO:29 is a peptide sequence of the invention.

SEQ ID NO:30 is a peptide sequence of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The subject invention concerns methods and materials for diagnosing,monitoring the progress, and/or providing a prognosis for multiplemyeloma and other diseases or conditions associated with antibodyproduction in a person or animal. In one embodiment, the disease orcondition is one characterized by excessive antibody production, and inparticular, excessive monoclonal antibody production. The methods of theinvention utilize mass spectrometry for quantitative monitoring anddetection of antibody produced by the plasma cells. The methods of theinvention can be utilized for diagnosis, monitoring, and/or prognosis ofmultiple myeloma, monoclonal gammopathy, and other immunological orhematological conditions and disorders. In addition to detecting andquantifying antibody in a sample, other biological markers, such asserum albumin and/or beta-2-microglobulin, can also be detected andquantified using the present invention, and in combination withdetection and quantification of antibody. Thus, in one embodiment, bothantibody and serum albumin and/or beta-2-microglobulin are detected andquantified using mass spectrometry and a diagnosis or prognosis madebased on the results and levels detected.

In one embodiment of a method of the present invention, a biologicalsample, such as a blood or serum sample, is treated to isolate thetarget protein therein. In one embodiment, the biological sample issubjected to size exclusion chromatography, gel electrophoresis, and/oraffinity chromatography to isolate the target protein. In a specificembodiment, the target protein is an antibody. The target protein isthen subjected to proteolytic fragmentation to create fragments of thetarget protein. In a specific embodiment, the target protein fragmentsare prepared by exposing the protein to trypsin for a sufficient periodof time. Other means for fragmentation of a target protein are known inthe art and can be used in the present methods. Optionally, the targetprotein can be denatured prior to fragmentation. In one embodiment,treatment of the target protein with urea and disulfide reduction andcysteine alkylation can be performed. Following fragmentation of thetarget protein into peptides, the peptides are subjected to massspectrometry to identify and quantify the levels of the target protein.In one embodiment, following proteolytic fragmentation and prior toquantitative mass spectrometry, the peptide fragments are separated byreverse phase chromatography and/or filtering by molecular weight. Usingthe results from several patient samples, specific peptides wereselected to monitor each type of antibody (A, D, E, G, and M), as wellas kappa and lambda light chain and other diagnostic molecules likeserum albumin and beta-2-microglobulin (see Table 1). In a specificembodiment, the fragmentation peptides of the target protein areALPAPIEK (SEQ ID NO:4) and/or DSTYSLSSTLTLSK (SEQ ID NO:28). Syntheticpeptides having an amino acid substitution or synthetic stableisotope-labeled peptides (e.g., comprising ²H, ¹³C, or ¹⁵N atoms in thepeptide molecule) having the same sequence as the fragmentation peptidescan be used as internal standards during the mass spectrometry toprovide for quantitation of the specific peptide fragments. The ratio ofthe peptide fragment to the isotope-labeled peptide standard can be usedto calculate the quantity of the target protein. In one embodiment, thepeptides are specific to heavy chains of human IgG, IgA, IgM, IgD, orIgE. In another embodiment, the peptides are specific to human kappa (κ)or lambda (λ) immunoglobulin light chains. In one embodiment, theinternal standard peptides can have an amino acid sequence shown in anyof SEQ ID NOs:1 to 30, or a fragment or variant thereof. In a specificembodiment, the synthetic internal standard peptide comprises the aminoacid of SEQ ID NO:4 or SEQ ID NO:28, or a fragment or variant thereof.In one embodiment, the mass spectrometry methods comprise liquidchromatography coupled to multiple reaction monitoring (LC-MRM) using atriple quadrupole mass spectrometer.

The subject invention also concerns peptides of target proteins, such asimmunoglobulin heavy chain, kappa light chain, lambda light chain, serumalbumin, and beta-2-microglobulin, that can be used in the methods ofthe present invention. In one embodiment, a peptide corresponds to aproteolytic digestion fragment of a human IgG, IgA, IgM, IgD, or IgEheavy chain, or a human kappa or lambda immunoglobulin light chain. Inone embodiment, a peptide of the invention comprises one or more stableheavy isotopes, such as ²H, ¹³C, or ¹⁵N. In another embodiment, apeptide of the invention comprises one or more amino acid substitutionsof similar composition (such as an alanine substituted for a glycine)from that of the sequence of target protein such that the subjectpeptide has a “mass shift” when compared to the corresponding peptidefragment of the target protein.

In a specific embodiment, a peptide of the invention comprises an aminoacid sequence shown in any of SEQ ID NOs:1 to 30, or a fragment orvariant thereof. In an exemplified embodiment, a peptide of theinvention has the amino acid sequence of SEQ ID NO:4 (for IgG heavychain) or SEQ ID NO:28 (for kappa light chain).

Biological samples refer to a fluid or tissue composition obtained froma human or animal. Biological samples within the scope of the inventioninclude, but are not limited to, whole blood, peripheral blood, bloodplasma, bone marrow, spleen, serum, urine, tears, saliva, sputum,exhaled breath, nasal secretions, pharyngeal exudates, bronchoalveolarlavage, tracheal aspirations, interstitial fluid, lymph fluid, meningalfluid, amniotic fluid, glandular fluid, feces, perspiration, mucous,vaginal or urethral secretion, cerebrospinal fluid, and transdermalexudate. A biological sample also includes experimentally separatedfractions of all of the preceding solutions or mixtures containinghomogenized solid material, such as feces, tissues, and biopsy samples.

The methods of the present invention can be used with humans and otheranimals. The other animals contemplated within the scope of theinvention include domesticated, agricultural, or zoo- orcircus-maintained animals. Domesticated animals include, for example,dogs, cats, rabbits, ferrets, guinea pigs, hamsters, pigs, monkeys orother primates, and gerbils. Agricultural animals include, for example,horses, mules, donkeys, burros, cattle, cows, pigs, sheep, andalligators. Zoo- or circus-maintained animals include, for example,lions, tigers, bears, camels, giraffes, hippopotamuses, andrhinoceroses.

All patents, patent applications, provisional applications, andpublications referred to or cited herein are incorporated by referencein their entirety, including all figures and tables, to the extent theyare not inconsistent with the explicit teachings of this specification.

Following are examples that illustrate procedures for practicing theinvention. These examples should not be construed as limiting. Allpercentages are by weight and all solvent mixture proportions are byvolume unless otherwise noted.

Example 1

In multiple myeloma, because each plasma cell secretes a uniqueantibody, the replication of the tumor cell and the progression ofdisease can be monitored by measuring the serum concentration of themonoclonal antibody it produces. Initial qualitative measurements aremade using serum protein electrophoresis (SPEP) and dye visualization(see FIGS. 1A and 1B). Separation of the serum proteins is achieved,isolating albumin from four regions of globulins, termed alpha 1 (α1),alpha 2 (α2), beta (β), and gamma (λ), described by the differences intheir migration relative to albumin. Normally, antibodies migrate intothe λ region, but are low in intensity compared to albumin and arepresent only as diffuse bands (FIG. 1A). The monoclonal antibodiesproduced in high concentration by multiple myeloma plasma cells can bevisualized as a single narrow, discrete, dark band usually in the λregion of the gel (FIG. 1B). Patients with abnormally high levels ofprotein in the gamma region can be diagnosed with multiple myeloma byidentifying the type of monoclonal antibody using immunofixationelectrophoresis (IFE), which is a separation similar to SPEP, but withspecific detection for each antibody chain (FIG. 2). Typical screenstest for immunoglobulin G, A, and M heavy chains, as well as kappa (κ)and lambda (λ) light chains. Immunoglobulin D or E myelomas are veryrare; when suspected, lanes of the standard IFE are replaced, enablingspecific detection of IgD or IgE heavy chain proteins. In the example,the patient has a tumor that produces an IgG κ monoclonal antibodyprotein (FIG. 2). The combination of these two tests establishes therelative amount and type of the antibody that is secreted by themultiple myeloma tumor cells. Gel-based techniques have recently beencomplemented by capillary array instruments that can analyze eightsamples in parallel, greatly increasing the throughput and lowering theamount of sample preparation necessary (tubes of serum are simply loadedinto the instrument, which automatically dilutes each sample in thebuffer used for capillary electrophoresis). SPEP and IFE are performedseparately.

The quantitative mass spectrometry methods of the invention can replacestandard art methods with a single analysis. Protein bands from SPEPhave been processed for protein identification using LC-MS/MS. Constantregions on an antibody are utilized in detection for quantitativemonitoring; as shown in FIG. 3, a peptide sequence ALPAPIEK (SEQ IDNO:4) is used to detect immunoglobulin G heavy chains. After generatingpeptides for monitoring each of the types of antibodies, a comprehensivemethod for antibody measurement was made. Briefly, minute volumes ofserum (1 to 10 μl) were processed for detection of each of the antibodychains: G, A, M, D. E, κ, and λ. After protein denaturation with urea,disulfide reduction, and cysteine alkylation, trypsin digestion wasperformed. The sample was then diluted and analyzed with liquidchromatography coupled to multiple reaction monitoring (LC-MRM) on atriple quadrupole mass spectrometer (FIG. 4). Methods for quantitativemass spectrometry of other proteins, such as vitellogenin,thyroglobulin, C-reactive protein, and others, have been described inU.S. Pat. Nos. 7,544,518 and 7,163,803; Published U.S. PatentApplication Nos. 2009/0011447 and 2009/0148951; and publications byAnderson and Hunter (2006) and Kuhn et al. (2004).

In one embodiment, the mass spectrometer instrument selectivelyquantifies peptides by filtering the m/z of the intact species in thefirst quadrupole (Q1), fragments the molecules in the second quadrupole(Q2), and filters the m/z of a particular fragment in the thirdquadrupole (Q3). Each of these peptide and fragment pairs is known as atransition; the instrument measures each transition as part of a cycle,continuously moving from one to the next. For each peptide, multipletransitions are monitored; the coincidence detection of multiplefragments from the peptide increases the confidence in the assignment.Each target protein can be quantified using more than one peptide. Whileseveral rules for peptide selection have been put forward, selection ofpeptides in biological or clinical context frequently deviates fromthose guidelines. Examples of quantification with LC-MRM are shown inFIGS. 5 and 6 using the ALPAPIEK (SEQ ID NO:4) peptide fromimmunoglobulin G (IgG) heavy chain and DSTYSLSSTLTLSK (SEQ ID NO:28)from the κ light chain. The ion signals corresponding to the y₅ and y₆ions of ALPAPIEK (SEQ ID NO:4) were detected at 22 minutes in FIG. 5; y₄were also monitored. The y₈, y₁₁, and y₁₂ ion signals for DSTYSLSSTLTLSK(SEQ ID NO:28) were detected at 28 minutes, as shown in FIG. 6. Theseion signals were confirmed from the sample used for the SPEP and IFE,illustrated with the diagrams in FIGS. 1 and 2.

The quantitative mass spectrometry assay of the present invention isadvantageous in animal models where limited amounts of blood serum canbe obtained. The implementation of a single quantitative test providesadvantages over the qualitative tests currently used to follow multiplemyeloma patients. The speed and parallel processing that can be achievedwith automated sample handling and MS detection will also significantlyimprove the throughput of patient samples. The adoption of the methodsof the invention at a tertiary cancer center will enable surroundingprimary care physicians and hospitals to send samples to a centralizedfacility for processing and analysis. Point of care patient sampling canbe performed with rapid turnaround of results to the treating physician(˜1 day) even at a centralized facility.

TABLE 1  Protein Peptide Sequence M/Z Transitions IGHA1, 2SAVQGPPER (SEQ ID NO: 1) 470.747 4 498.268 5 555.289 6 683.348 IGHA1, 2WLQGSQELPR (SEQ ID NO: 2) 607.320 6 729.390 7 786.411 8 914.470WLQGSQELPR (SEQ ID NO: 2) 610.820 6 736.390 7 793.411 8 921.470 IGHA1TPLTATLSK (SEQ ID NO: 3) 466.277 5 519.314 6 620.362 7 733.446TPLTATLSK (SEQ ID NO: 3) 469.777 5 526.314 6 627.362 7 740.446 IGHG1, 3ALPAPIEK (SEQ ID NO: 4) 419.756 4 486.293 5 557.330 6 654.383 IGHG1, 2EPQVYTLPPSR 643.841 4 456.257 6 670.389 7 88.452 (SEQ ID NO: 5)DPQVYTLPPSR 636.833 4 456.257 6 670.389 7 833.452 (SEQ ID NO: 6) IGHG1GPSVFPLAPSSK 593.828 8 846.473 9 945.541 10 1032.573 (SEQ ID NO: 7)GPSVFPLAPSSK 596.828 8 852.472 9 951.540 10 1038.573 (SEQ ID NO: 7)IGHG2 GLPAPIEK (SEQ ID NO: 8) 412.748 4 486.293 5 557.240 6 654.383GLPAPIEK (SEQ ID NO: 8) 415.748 4 492.293 5 563.330 6 660.383 IGHG3WYVDGVEVHNAK 708.850 6 697.363 9 968.480 11 1230.612 (SEQ ID NO: 9)WYVDGVEVHNAK 711.850 6 703.363 9 974.480 11 1236.611 (SEQ ID NO: 9)IGHG3, 4 VVSVLTVLHQDWLNGK 904.507 5 617.341 10 1209.638 11 1310.686(SEQ ID NO: 10) IGHG4 SLSLSLGK (SEQ ID NO: 11) 402.746 5 517.335 6604.367 7 717.451 IGHM DGFFGNPR (SEQ ID NO: 12) 455.215 4 443.237 5590.305 7 794.394 DAFFGNPR (SEQ ID NO: 13) 462.223 4 443.237 5 590.305 7808.410 IGHM QVGSGVTTDQVQAEAK 809.408 8 888.443 9 989.490 10 1090.538(SEQ ID NO: 14) IGKC VDNALQSGNSQESVTEQDSK 1068.489 6 707.321 14 1495.6518 893.421 (SEQ ID NO: 15) IGKC TVAAPSVFIFPPSDEQLK 978.518 8 913.463 91060.532 11 1320.684 (SEQ ID NO: 16) TVGAPSVFIFPPSDEQLK 966.510 8913.463 9 1060.532 11 1320.684 (SEQ ID NO: 17) LAC AAPSVTLFPPSSEELQNK993.513 10 1102.538 11 1199.591 12 1346.659 (SEQ ID NO: 18) LACAGVETTTPSK 495.759 5 533.294 6 634.341 7 763.384 (SEQ ID NO: 19)AGVETTTPSK 498.759 5 539.294 6 640.341 7 769.384 (SEQ ID NO: 19) IGHEGSGFFVFSR (SEQ ID NO: 20) 502.254 5 655.357 6 802.425 7 859.447GSAFFVFSR (SEQ ID NO: 21) 506.262 5 655.357 6 802.425 7 873.462 IGHDEPAAQAPVK (SEQ ID NO: 22) 455.754 5 542.330 6 613.367 7 684.404EPAGQAPVK (SEQ ID NO: 23) 448.746 5 542.330 6 599.351 7 670.388 IGHDVRPGGVEEGLLER 678.362 7 845.437 10 1058.548 11 1159.596 (SEQ ID NO: 24)ALBU LVNEVTEFAK 575.312 6 694.378 7 823.420 8 937.463 (SEQ ID NO: 25)LVNDVTEFAK 568.303 6 694.378 7 809.404 8 923.447 (SEQ ID NO: 26) ALBUAEFAEVSK (SEQ ID NO: 27) 440.725 5 533.294 6 680.362 7 809.404 Table 1displays a list of monitored peptides of interest and theircorresponding standards (where applicable) along with the Y-iontransitions used in MRM. The underlining designates an amino acid thatcan be labeled with a stable heavy isotope.

It should be understood that the examples and embodiments describedherein are for illustrative purposes only and that various modificationsor changes in light thereof will be suggested to persons skilled in theart and are to be included within the spirit and purview of thisapplication and the scope of the appended claims. In addition, anyelements or limitations of any invention or embodiment thereof disclosedherein can be combined with any and/or all other elements or limitations(individually or in any combination) or any other invention orembodiment thereof disclosed herein, and all such combinations arecontemplated with the scope of the invention without limitation thereto.

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1-3. (canceled)
 4. A method for diagnosing, monitoring the progress of,and/or providing a prognosis of multiple myeloma (MM) or monoclonalgammopathy of undetermined significance (MGUS) in a person or animal,said method comprising (a) isolating a target protein from a biologicalsample from the person or animal, wherein the target protein comprisesserum albumin, beta-2-microglobulin, or a combination thereof; (b)fragmenting the target protein to create peptide fragments thereof; (c)subjecting the peptide fragments of the target protein to quantitativemass spectrometry to identify and quantitate the amount of targetprotein in the biological sample; and (e) using the identity andquantity of the target protein in the biological sample to diagnose,monitor the progress of, and/or provide the prognosis of the MM or MGUSin the person or animal.
 5. (canceled)
 6. (canceled)
 7. (canceled) 8.(canceled)
 9. (canceled)
 10. The method according to claim 4, whereinthe target protein is identified and quantitated by spiking in a knownamount of a specific labeled peptide corresponding to a fragment of atarget protein during mass spectrometry, wherein the specific labeledpeptide comprises a heavy isotope label or has an amino acidsubstitution to create a mass difference between the fragment of thetarget protein and the specific labeled peptide.
 11. The methodaccording to claim 10, wherein the heavy isotope label is ²H, ¹³C, or¹⁵N.
 12. (canceled)
 13. (canceled)
 14. (canceled)
 15. (canceled) 16.(canceled)
 17. (canceled)
 18. The method according to claim 4, whereinthe target protein is denatured prior to fragmentation.
 19. The methodaccording to claim 18, wherein the target protein is denatured bytreatment with urea, disulfide reduction, and/or cysteine alkylation.20. The method according to claim 4, wherein the target protein isfragmented by proteolytic enzyme digestion.
 21. The method according toclaim 20, wherein the proteolytic enzyme is trypsin.
 22. The methodaccording to claim 4, wherein said treating step comprises one or moreof size exclusion chromatography, gel electrophoresis, and/or affinitychromatography to isolate the target protein.
 23. The method accordingto claim 4, wherein the mass spectrometry comprises liquidchromatography coupled to multiple reaction monitoring (LC-MRM).
 24. Themethod according to claim 23, wherein the mass spectrometry is conductedon a triple quadrupole mass spectrometer.
 25. The method according toclaim 10, wherein the amino acid substitution comprises substitution ofalanine for glycine.
 26. The method according to claim 4, wherein themethod is used to monitor for progression of monoclonal gammopathy ofundetermined significance in the person or animal to multiple myeloma.27. The method according to claim 4, wherein the method is used tomonitor the efficacy of a treatment regimen on a person or animal withmultiple myeloma or MGUS.
 28. The method according to claim 1, furthercomprising treating the subject for MM or MGUS if the identity andquantity of the target protein in the biological sample indicateselevated levels of serum albumin, beta-2-microglobulin, or a combinationthereof, in the person or animal.